Half to william dunn



LAWRENCE DUNN, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR OF ONE- HALF -TO WILLIAM DUNN, OF `SAME PLACE.

DOOR-OPEN ER.

SPECIFICATION forming' part of Letters PatentNO. 538,900, dated May 7, 1895.

Application filed February 26, 1895. Serial No. 53.9,'769. o model.)

To all whom it may concern:

Beit known that I, LAWRENCE DUNN, a citizen of the United States, residing in the city and county of San Francisco, State of California, have invented an Improvement in Door and Gate Openers; and I hereby declare the following to be a full, clear, and exact description of the same.

My invention relates to a device which is designed to open doors, gates and other closures, and it is especially adapted for use upon fire engine houses where it is necessary to open the doors the instant the horses are attached to the engine or other apparatus, so as to al- 10W them to move out instantly.

It consists in certain details of construction, which will be more fully explained by reference to the accompanying drawing, in which the figure is an interior view of a door with my device attached to it.

A A are doors hinged at opposite sides and meeting in the center Where double doors are used. In case of a single door the apparatus can be applied to the one as well as two. The doors are normallykept closed by spring-actuated pins or latches B which are fixed to the Wall or frame-Work above the doors, and are adapted to engage with locking arms C, one

of which is fixed to each door so that whenthe doors are closed they project inwardly in line With the pins B, and the springs force the pins to engage the holes or locking notches on the arms. From the upper ends of the pins B cords D extend a short distance upward uniting into a single cord which passes over guide pulleys as shown at E, so that the cord will lead to a point above the drivers seat on the engine, depending with a suitable handle within easy reach of the driver so that when the horses are Vproperly attached, it is only necessary to pull upon the cord to release the doors and the opening mechanism then acts to throw them Wide open. This mechanism consists of levers F which are fulcrumed at f beneath the upper part of the door-frame or casing, and have their outer ends adapted to press against the inner sides of the doors. In order to relieve them from friction as much as possible, these outer ends have anti-friction rollers G journaled in them. The inner ends are connected by links H with lever arms I, the opposite ends of which are also fulcrumed or pivoted at t' to the top of the door casing at a point near to the fulcrum of the levers F. At the point h Where the link H joins the lever I, a cord J is attached, passing thence around a pulley K pivoted upon the door casing, passing thence over a pulley L and thence passing down to a Weight M.

For convenience, the cords Will pass through guide tubes N fixed upon the sides of the engine room, and may lead down through the floor so that the weights M will be suspended in the basement. It will, however, be manifest that the Weights might be arranged Within the room itself, or the cord directed by other pulleys so that the weights could be arranged in rooms or spaces above the engine room if more convenient, the operation being essentially the same in each case.

In place of the Weights, the doors may be thrown open, if preferred, by springs'which are compressed when the doors are closed, and which act, when they are released from their holding catches, to force them open again.

It will be manifest from the limited Width of the casing above the door, that when the doors are closed, the levers F and I must lie Very closely to each other, and the arrangement of the cords is such that the Weight cannot act readily until the doors have been moved a short distance. In order to overcome this difficulty, I have, therefore, shown the intermediate levers I, and the connecting links H with the cords connecting with their j unction point so that when the door is released and the Weight acts upon the cord to pull upon thc levers, the action of the inner end of the lever I is such as to move the latter around its fulcrum pin and thus increase the leverage, which, in turn, acts directly through the link H upon the lever F so as to quickly open the doors. When closed the levers are again folded in their place and the latches engage the doors and hold them until such time as it is again desired to open them.

Having thus described my invention, what ICO the inner faces of the doors, and weights connected with the inner ends of the levers so that when the doors are unlatched the weights will act to force them open.

2. A gate or door opening device consisting of a lever fulerumed beneath the top of the door casing having an anti-frictional roller journaled in the outer end pressing against the inner side of the door, a second lever ful erunied to the casing near to the first one, a link connecting,r the inner ends of the two levers, a cord for operating the levers, and direction pulleys around which it passes and a weight acting through the cord and upon the levers.

3. In a gate or door opening device, levers fulcrumed to the top of the door easing one of said levers pressing against the door, a link by which the movable inner ends of the levers are connected, a weighted cord for operating zo the levers, and direction pulleys around which it passes, a latehing device by which the doors are retained in a closed position against the action of the weights, and cords passing over direction pulleys therefrom whereby the doors 25 may be released.

In witness whereof I have hereunto set my 

